Engine Noise

*ENGINE NOISE

- When Monitored:

When standing in front of the truck with engine running, several distinct noises may be heard, these noises may vary depending on listener location, 2WD vs. 4WD, engine temperature and miles on vehicle.


1. GEAR TRAIN NOISE EVALUATION

Normal : Gear noise is noticeable when standing in front of the engine, may vary with engine temperature, engine speed, engine load, miles on vehicle, and from engine to engine.

Abnormal: Gears are visually damaged or have backlash or end clearance out of specification. The cause should be identified and corrected.

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2. FUEL PUMP NOISE EVALUATION

Normal : Pumping noise may vary - the fuel pump is producing between 5,000 and 20,000 psi depending on operating conditions.

Abnormal: A fuel pump with excessive pressure variation (± 500 psi from setpoint) is abnormal. The cause should be identified and corrected, refer to Engine Surge or Engine Difficult to Start symptoms.

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3. INJECTOR NOISE EVALUATION

Normal: Combustion noise may vary at different operating conditions. May be more noticeable on throttle tip-in and vary from engine to engine.

Abnormal: Loud knock with smoke and vibration. Cylinder cut out test or mechanical blocking of injectors (injector block off 9011) should be used to identify failed injectors.

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4. VALVE TRAIN NOISE EVALUATION

Normal: Valve settings are correct and no visual damage to parts.

Abnormal: If valve settings are out of specification, they should be reset. Also, correct for any damage to rocker levers, push rods, or crossheads.

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- Refer to Engine / Testing and Inspection for other types of noise and causes.